SURVEYING THE OCEANS (HYDROGRAPHIC) 



Hydrography is the science of measurement and description of 

 the physical features of the oceans, seas, lakes, rivers, and other 

 waters and their adjoining coastal areas, with particular reference 

 to their use for navigational purposes. Hydrographic surveying 

 is the process of making these measurements. In addition to 

 serving as source material for nautical charts. Sailing Directions, 

 and other publications for the Navy's operating Fleet and the 

 country's merchant marine, results of the surveys are used in 

 planning harbor improvements and in meeting various defense 

 requirements, as well as for studies of silting and erosion. 



Only a small part of the ocean has been adequately surveyed. 

 The changes caused by nature and man, and the continual increase 

 in requirements for more precise and more nearly automatic 

 systems and methods of navigation, render obsolete the charts 

 or surveys once considered adequate. Consequently, the need for 

 more accurate and complete surveys continues. 



Small sounding boats carried by survey ships 

 are used to survey shallow water areas. 



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